Extracted 08JAN2012 from http://www.npr.org/blogs/health/2013/01/07/168616995/why-exercise-may-do-a-te... Exercise is a powerful enabler for a healthy mental life but this research is as much about fun in overcoming obstacles together with those who are or may become friends ("winning with friends").
So it is about sports, right? Well, yes, but it also can apply to situations that don't even involve competition against others although such common situations are harder to define in general because the "small wins" in collaborative work are idiosyncratic and situation specific (see. e.g., <a href="http://islets.posterous.com/the-power-of-small-wins-by-teresa-m-amabile-a).
There are ways to "measure" intangibles that make all the difference in collaborative work that involves a subtle combination of mental, physical, and social skill (see, e.g., <a href="http://www.scribd.com/collections/2695573/Collection-3-4-Theoretical-Foundations-for-Outcomes-Based-Training-and-Education-in-an-Ambiguous-and-Changing-World).
In the world of (online) games, intangibles can provide metrics that drive individual motivation and the pursuit of excellence within which fun and competition has deeper (epic) meaning (see, e.g., <a href="http://www.thedivisionigr.com/ranking-system.html).